Tuesday, October 6, 2015
Some bubbles with Famo.us's physic engine in CoffeeScript and Meteor.js
Introduction
A week ago, Raix, the author of Famono package used for integrating Require.js and Famo.us with Meteor.js, has published a new release that simplifies greatly the integration.
I was willing to demonstrate just that when a nice demo of Famo.us's physic engine has shown up on my radar: http://hbsand.com/HappyBoxes/. So why not demonstrating both?
You can access the live demo here: http://famousbubble.meteor.com/.
You can also clone the code repository from Github: https://github.com/PEM--/famousbubble
Note for Chrome users on OSX : The current release of Chrome, the 36, has a bug that stops the demo running after ~1-2s. This bug is fixed in Chrome Canary version 37. I didn't see it on the current Chrome for Android or iOS. Firefox and Safari work well on OSX.
I was willing to demonstrate just that when a nice demo of Famo.us's physic engine has shown up on my radar: http://hbsand.com/HappyBoxes/. So why not demonstrating both?
You can access the live demo here: http://famousbubble.meteor.com/.
You can also clone the code repository from Github: https://github.com/PEM--/famousbubble
Note for Chrome users on OSX : The current release of Chrome, the 36, has a bug that stops the demo running after ~1-2s. This bug is fixed in Chrome Canary version 37. I didn't see it on the current Chrome for Android or iOS. Firefox and Safari work well on OSX.
Preparing your development environment
So, lets get down to business. The first step is to create the app:
mrt create FamousBubble
cd FamousBubble
rm -rf FamousBubble.*
mkdir -p client/stylesheets client/startup client/views
mrt add coffeescript
mrt add stylus
mrt add jade
mrt add famono
For the imported Require.js package, I keep it at the bare minimum. Famono places the imported packages from a file called
client/lib/smart.require
:{This has not changed from the early version.
"famous": {
"git": "https://github.com/Famous/famous.git"
},
"famousPolyfills": {
"git": "https://github.com/Famous/polyfills.git"
}
}
Linking Famo.us with Meteor.js
In Famono, what has changed is the way you require your dependencies. Theclient/startup/famous.coffee
is greatly reduced:# This is equivalent to: require 'famousPolyfills'
famousPolyfills
# Identically, this is equivalent to: require 'famous.core.famous'
famous.core.famous
# Declaring the main context
window.mainCtx = famous.core.Engine.createContext()
Everything is now imported into the main context of Meteor.js. There is no more boilerplate code.
Our main Jade file,
client/index.jade
stays unchanged:head
title Famo.us - Physic demo
meta(name='viewport', content='width=device-width, maximum-scale=1, user-scalable=no')
meta(name='mobile-web-app-capable', content='yes')
meta(name='apple-mobile-web-app-capable', content='yes')
meta(name='apple-mobile-web-app-status-bar-style', content='black')
body
+index
template(name='index')
The Styus file,
client/stylesheets/app.styl
, is also unchanged:@import nib
html
font-family: Helvetica, Arial, sans-serif
*
-webkit-user-drag: none
body
-webkit-user-callout: none
user-select: none
background-color: #FF851B
Like the former file, the associated CoffeeScript file
client/index.coffee
to the index
template is almost unchanged either:Template.index.rendered = ->
$(document).ready ->
window.appView = new AppView()
mainCtx.add appView
appView.addDragger()
appView.addBubbles()
Easier subclassing
As the Famo.us's University told us, you create your views by inheriting from Famo.us's ones. With Famono, it is now simplified. Here the code for theAppView
, client/views/AppView.coffee
that we just call in the previous file, the index
template:class @AppView extends famous.core.ViewAs you can see it, the inheritance from a Famo.us's
DEFAULT_OPTIONS:
numBodies: 10
gravity: [0, 0.0015, 0]
constructor: (@options)->
@constructor.DEFAULT_OPTIONS = @DEFAULT_OPTIONS
super @options
surf = new famous.core.Surface
size: [400, 400]
properties:
backgroundColor: '#FFDC00'
borderRadius: '8px'
mod = new famous.core.Modifier
origin: [.5, .5]
@add(mod).add surf
@gravity = new famous.physics.forces.Force @options.gravity
@ceiling = new famous.physics.constraints.Wall
normal: [0, 1, 0]
distance: 200
restitution: 0
@floor = new famous.physics.constraints.Wall
normal: [0, -1, 0]
distance: 200
restitution: 0
@left = new famous.physics.constraints.Wall
normal: [1, 0, 0]
distance: 200
restitution: 0
@right = new famous.physics.constraints.Wall
normal: [-1, 0, 0]
distance: 200
restitution: 0
@pe = new famous.physics.PhysicsEngine()
@collision = new famous.physics.constraints.Collision restitution: 0
@bubbleBodies = []
famous.inputs.GenericSync.register
'mouse': famous.inputs.MouseSync
'touch': famous.inputs.TouchSync
addDragger: ->
@dragger = new Dragger()
@pe.addBody @dragger.body
(@_add @dragger.state).add @dragger.shape
sync = new famous.inputs.GenericSync ['mouse', 'touch']
@dragger.shape.pipe sync
sync.on 'update', (data) =>
@dragger.position[0] += data.delta[0]
@dragger.position[1] += data.delta[1]
@dragger.body.setPosition @dragger.position
addBubble: (i) =>
bubble = new Bubble()
@pe.addBody bubble.body
bubble.state.transformFrom =>
@gravity.applyForce bubble.body
bubble.body.getTransform()
(@add bubble.state).add bubble.shape
@pe.attach [@right, @left, @floor, @ceiling], bubble.body
(@pe.attach @collision, @bubbleBodies, bubble.body) if i > 0
@pe.attach @collision, [bubble.body], @dragger.body
@bubbleBodies.push bubble.body
addBubbles: ->
[0...@options.numBodies].map (i) =>
famous.utilities.Timer.setTimeout (@addBubble.bind @, i), 1000
View
does not require you to wait for Famo.us to be loaded in your document. Additionally, the require step has been greatly simplified. Calling any class provided by Famo.us is done with a simple namespaced call.I've create 2 more classes. The first one,
client/views/Dragger.coffee
concerns the little dragging bubble used to play with the blue bubbles:class @Dragger
RADIUS: 30
constructor: ->
@shape = new famous.core.Surface
size: [2 * @RADIUS, 2 * @RADIUS]
properties:
border: '2px solid #FF4136'
borderRadius: "#{2 * @RADIUS}px"
backgroundColor: 'rgba(255, 255, 255, 0.5)'
@body = new famous.physics.bodies.Circle
radius: @RADIUS
mass: 5
@position = [0, 0]
@state = new famous.core.Modifier
origin: [.5, .5]
transform: =>
famous.core.Transform.translate @position[0], @position[1], 0
The second one,
client/view/Bubble.coffee
concerns the bubble themselves: class @Bubble
constructor: ->
radius = famous.math.Random.integer 20, 60
@shape = new famous.core.Surface
size: [radius * 2, radius * 2]
properties:
backgroundColor: '#7FDBFF'
border: '3px solid #0074D9'
borderRadius: "#{radius}px"
@body = new famous.physics.bodies.Circle radius: radius, mass: 2
@state = new famous.core.Modifier origin: [.5, .5]
Conclusion
With the new Famono release, integrating Famo.us and Meteor.js is simpler than ever. My little sample is missing few things. A better separation of the controller from the views would be great. But, there is some upcoming Famo.us lessons that should arrive in the Famo.us's University. Therefore, they will surely cover their best practices. No rush.
Labels:
Atom.io,
CoffeeScript,
Famo.us,
Meteor.js
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